Jeep Grand Cherokee alternator

I have a 2012 Jeep Grand Cherokee with a 3.0L V6 engine producing 241 horsepower, and the alternator is not working.
It appears that the controller is already bus-controlled.
I tried testing the alternator on a test bench with an external regulator, but when I connected it, the test bench didn't reach its rated speed. So, I disconnected the D+ cable, let the alternator run, and then briefly touched the D+ voltage. However, the alternator then charges so much that the test bench immediately shuts down. I can only do it for a very short time, which means I can't determine whether it's working correctly or not. I wanted to test the LIM (likely referring to a current limiter) and check with the oscilloscope to see if perhaps a diode is also faulty.

I then checked the cable that goes to the regulator on the car with the oscilloscope while the ignition was on. See image.

The way the car arrived was with the cable disconnected from the regulator, and I have no idea if the person who broke down tried to do anything.
My concern is that the alternator and regulator might not be related at all, because it might be like with the newer VAG vehicles, where you have to tell the tester that the alternator is being powered when you test it. I turned on the front and rear window heaters, but the voltage remained below 12V.

How do you test a LIN-BUS alternator on a test bench? Does anyone know if this Jeep has a similar feature to the new VAG vehicles, where it can recharge its battery through regenerative braking?

Thank you.

Perhaps this will help a little more:
I am sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

The excitation current should be pulse-width modulated (i.e., not voltage-controlled). This also matches the observed image. What types of connectors are available (name/description)?
hg
Herbert.

"Thanks, Herbert, I've already seen that."

This regulator has three terminals, but there's only one cable connected to the plug, and I measured voltage on that cable when the ignition is on, without the alternator connected. There's also no label on it.
It might be a PWM signal instead of a LIN signal, although according to kfz.de, only the LIN controllers have one cable.
Is it a Denso alternator?

I've already tried using an external regulator with many Limas that have a multi-function regulator, and it's always worked, most recently with an Alfa. I've always done it this way to be sure that the problem lies with the regulator. In the case of the Alfa, I then saw on the oscilloscope that a plus diode was also defective.

Here's something I found: http://www.cascospa.net/Catalog.aspx?ID=CAL40415. According to this product catalog, the upper bracket is installed, but as I understand it, you could also use the lower one. However, the mounting points and connections are reversed on the lower bracket.

EDIT:
The link only works for a limited time.
Here is the picture.

There must be at least some kind of output for the charging control in the AI.
Does Denso provide any information about the pinout?
hg
Herbert.

I believe that the charging control is deactivated by the onboard computer or the body control module when the corresponding module receives a sufficiently high voltage. It no longer has a charging control in the traditional sense; it only illuminates when it is not charging. I also believe that the preheating coil glows in the same area, but I need to check that again when I'm in the workshop.

I've reviewed a few wiring diagrams (VAG) for vehicles equipped with a start-stop system (including the Jeep), and all of them have a LIN-bus controlled regulator. And all of them have only one wire connected to the regulator, which goes to the gateway and the battery management system.

Back to square one: What exactly was the error message? Was it with or without a connected LIN connection? Can you read the error codes?

The generator, along with its associated regulator, should be able to operate in a kind of emergency mode on your test bench, even without a LIN connection, possibly with a battery as a buffer. Does it provide any output (voltage, current, ripple)?

hg
Herbert.

The car broke down and was towed away by the roadside assistance service. The voltage while the engine was running was 11.76V. I then tried to remove the alternator, and that's when I saw that the cable wasn't connected to the regulator.
"Cables connected, engine started, all consumers powered on, but the voltage is back down to around 11.5V."

I ran the Lima (alternator) again and connected the regulator while it was running. The voltage went up to 14.7V, the current reached a few amps, and the test bench started to fail. Then I measured it with the oscilloscope, and it looked like one of the diodes was faulty.

I then disassembled the diode plate, something I initially wanted to avoid, because the windings are inductively welded to the diode plate, and it's not easy to separate them.

When testing the diodes with a 60W lamp, a short circuit was detected in one of the negative diodes.

I still don't know if the regulator was also affected. Ask about the price of the diode plate and regulator tomorrow.

Unfortunately, there are no replacement parts available.

Does anyone know of any companies that sell replacement starter motors and alternators?

Basically, only parts from Bosch or Valeo can be replaced; you should inquire with Bosch Service about this.

chli1976 wrote:

Unfortunately, there are no spare parts available. Does anyone know of any companies where you can get starter and alternator replacement parts?

Try your luck here: http://www.hb-elektrik.de. They are very kind and competent.

Is it even possible in this case to source and replace the diode(s) individually?
What is the part number or identification marking on the diodes (in the photo)?
hg
Herbert.

Thanks, vag-driver, for the link. I'll contact you again if my supplier can't help me.

Herbert.
I wanted to replace the entire diode board, not just a single diode. I'm familiar with that concept from the past, but I've never actually done it myself.
As a temporary fix, and when I couldn't wait, I used to cut a diode with a heatsink from an old diode plate, run a wire from the stator winding to the outside, and then screw the diode either to ground or to the positive terminal of the alternator.

But with a 220A Lima output, it wouldn't have lasted long.